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<head><meta charset="utf-8"><title>issue #80706 – ICE stable-stable regression · wg-async-foundations · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/187312-wg-async-foundations/index.html">wg-async-foundations</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/187312-wg-async-foundations/topic/issue.20.2380706.20.E2.80.93.C2.A0ICE.20stable-stable.20regression.html">issue #80706 – ICE stable-stable regression</a></h3>

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<a name="223565809"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/187312-wg-async-foundations/topic/issue%20%2380706%20%E2%80%93%C2%A0ICE%20stable-stable%20regression/near/223565809" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> tmandry <a href="https://rust-lang.github.io/zulip_archive/stream/187312-wg-async-foundations/topic/issue.20.2380706.20.E2.80.93.C2.A0ICE.20stable-stable.20regression.html#223565809">(Jan 21 2021 at 20:26)</a>:</h4>
<p><span class="user-mention" data-user-id="216206">@lcnr</span> did you see <a href="https://github.com/rust-lang/rust/issues/80706#issuecomment-759871986">this comment</a>?</p>



<a name="223565868"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/187312-wg-async-foundations/topic/issue%20%2380706%20%E2%80%93%C2%A0ICE%20stable-stable%20regression/near/223565868" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> tmandry <a href="https://rust-lang.github.io/zulip_archive/stream/187312-wg-async-foundations/topic/issue.20.2380706.20.E2.80.93.C2.A0ICE.20stable-stable.20regression.html#223565868">(Jan 21 2021 at 20:27)</a>:</h4>
<p>I've been too swamped to go in and debug what was happening, wondering if you had any ideas</p>



<a name="223565917"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/187312-wg-async-foundations/topic/issue%20%2380706%20%E2%80%93%C2%A0ICE%20stable-stable%20regression/near/223565917" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> tmandry <a href="https://rust-lang.github.io/zulip_archive/stream/187312-wg-async-foundations/topic/issue.20.2380706.20.E2.80.93.C2.A0ICE.20stable-stable.20regression.html#223565917">(Jan 21 2021 at 20:27)</a>:</h4>
<p>basically, we end up with unnormalized types in MIR after <a href="https://github.com/rust-lang/rust/issues/78410">#78410</a></p>



<a name="223565968"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/187312-wg-async-foundations/topic/issue%20%2380706%20%E2%80%93%C2%A0ICE%20stable-stable%20regression/near/223565968" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> tmandry <a href="https://rust-lang.github.io/zulip_archive/stream/187312-wg-async-foundations/topic/issue.20.2380706.20.E2.80.93.C2.A0ICE.20stable-stable.20regression.html#223565968">(Jan 21 2021 at 20:28)</a>:</h4>
<p>and this causes an ICE when producing debuginfo for those types</p>



<a name="223568810"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/187312-wg-async-foundations/topic/issue%20%2380706%20%E2%80%93%C2%A0ICE%20stable-stable%20regression/near/223568810" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/187312-wg-async-foundations/topic/issue.20.2380706.20.E2.80.93.C2.A0ICE.20stable-stable.20regression.html#223568810">(Jan 21 2021 at 20:53)</a>:</h4>
<p>i did see that comment but didn't take the time to look too deeply into this</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/187312-wg-async-foundations/topic/issue%20%2380706%20%E2%80%93%C2%A0ICE%20stable-stable%20regression/near/223568990" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/187312-wg-async-foundations/topic/issue.20.2380706.20.E2.80.93.C2.A0ICE.20stable-stable.20regression.html#223568990">(Jan 21 2021 at 20:55)</a>:</h4>
<p>i expect the error to be caused by us only normalizing opaque types and not projections somewhere?</p>



<a name="223569165"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/187312-wg-async-foundations/topic/issue%20%2380706%20%E2%80%93%C2%A0ICE%20stable-stable%20regression/near/223569165" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/187312-wg-async-foundations/topic/issue.20.2380706.20.E2.80.93.C2.A0ICE.20stable-stable.20regression.html#223569165">(Jan 21 2021 at 20:56)</a>:</h4>
<p>if the ice was caused by an opaque type in layout it would be quite straightforward and probably a wont-fix for now unless we figure out how to remove duplicate subtypes in generators</p>



<a name="223570922"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/187312-wg-async-foundations/topic/issue%20%2380706%20%E2%80%93%C2%A0ICE%20stable-stable%20regression/near/223570922" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/187312-wg-async-foundations/topic/issue.20.2380706.20.E2.80.93.C2.A0ICE.20stable-stable.20regression.html#223570922">(Jan 21 2021 at 21:11)</a>:</h4>
<p>hmm, it seems really weird to me that we ICE on the inner projection instead of the opaque type</p>



<a name="223571365"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/187312-wg-async-foundations/topic/issue%20%2380706%20%E2%80%93%C2%A0ICE%20stable-stable%20regression/near/223571365" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/187312-wg-async-foundations/topic/issue.20.2380706.20.E2.80.93.C2.A0ICE.20stable-stable.20regression.html#223571365">(Jan 21 2021 at 21:15)</a>:</h4>
<p>I think it would make sense to search for the place where we finally normalize the opaque type and find out why we don't normalize the inner projection as well</p>



<a name="223571922"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/187312-wg-async-foundations/topic/issue%20%2380706%20%E2%80%93%C2%A0ICE%20stable-stable%20regression/near/223571922" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/187312-wg-async-foundations/topic/issue.20.2380706.20.E2.80.93.C2.A0ICE.20stable-stable.20regression.html#223571922">(Jan 21 2021 at 21:19)</a>:</h4>
<p>it caused an ICE before <a href="https://github.com/rust-lang/rust/issues/75443">#75443</a> <a href="https://rust.godbolt.org/z/x6Krce">https://rust.godbolt.org/z/x6Krce</a> so it definitely seems to work if we always normalize opaque types</p>



<a name="223572042"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/187312-wg-async-foundations/topic/issue%20%2380706%20%E2%80%93%C2%A0ICE%20stable-stable%20regression/near/223572042" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/187312-wg-async-foundations/topic/issue.20.2380706.20.E2.80.93.C2.A0ICE.20stable-stable.20regression.html#223572042">(Jan 21 2021 at 21:20)</a>:</h4>
<p>don't have the time to spend an evening or two looking into this myself though</p>



<a name="223572189"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/187312-wg-async-foundations/topic/issue%20%2380706%20%E2%80%93%C2%A0ICE%20stable-stable%20regression/near/223572189" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/187312-wg-async-foundations/topic/issue.20.2380706.20.E2.80.93.C2.A0ICE.20stable-stable.20regression.html#223572189">(Jan 21 2021 at 21:22)</a>:</h4>
<p><span class="user-mention silent" data-user-id="216206">lcnr</span> <a href="#narrow/stream/187312-wg-async-foundations/topic/issue.20.2380706.20.E2.80.93.C2.A0ICE.20stable-stable.20regression/near/223568990">said</a>:</p>
<blockquote>
<p>i expect the error to be caused by us only normalizing opaque types and not projections somewhere?</p>
</blockquote>
<p>^ doesn't seem like this is the case, but we instead normalize the opaque type and then fail to normalize the projection which seems really weird to me</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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